Method and apparatus for controlling in situ waste remediation

Abstract

An in situ waste treatment system for contaminated soil employs a high temperature energy probe which is lowered into a borehole casing that has been inserted into the contaminated soil. The energy probe is activated and then melts surrounding region of the contaminated soil. The probe is raised and continues to melt a cylindrical column of soil that surrounds the borehole casing. Oxygen is introduced into the molten material so that organic and metallic components thereof are oxidized. In basaltic soils superheating and nucleation materials are introduced to enhance formation of a crystalline structure in the contaminated soil as it solidifies. Increased crystallinity makes the resultant solidified basaltic materials more resistant to leaching by ground water. Other types of contaminated soils are treated with waste modifiers to produce optimum leach resistance of the resultant resolidified soil.

What is claimed is: 
     
       1. Apparatus for in situ treatment and oxidation of waste materials in contaminated soil comprising: a movable energy probe capable of melting the contaminated soil;   means for introducing the energy probe into the contaminated soil to a predetermined depth;   means for activating the energy probe after the probe is inserted to the predetermined depth;   means for maintaining the energy probe at a predetermined location for a period of time sufficient to permit at least about one cubic foot of adjacent contaminated soil to become molten;   means for introducing oxygen rich substances to the molten soil; and   means for controlling the amount of introduced oxygen to (a) preclude a reducing reaction between any carbon bearing components and any metallic components of the waste materials and to (b) produce metallic oxides from the metallic components which oxides dissolve into the molten waste material.   
     
     
       2. The apparatus of claim 1 which further comprises: means for raising the energy probe above the predetermined starting depth while maintaining the energy probe in an activated state;   means for controlling the rate of ascent of the probe so that the contaminated soil which becomes adjacent to the probe during its ascent is melted and its organic and metallic components are oxidized; and   wherein the rate of ascent is controlled to permit the energy probe to superheat the adjacent contaminated soil and thereby produce enhanced opportunity for formation of metallic oxide crystals within the contaminated soil during solidification thereof.   
     
     
       3. The apparatus of claim 1 which further comprises means for introducing waste form modifiers into the molten contaminated soil to produce a basaltic rock from the resolidified contaminated soil. 
     
     
       4. The apparatus of claim 1 which further comprises means for introducing neucleation sites into the molten contaminated soil to enhance crystal formation within the contaminated soil during re-solidification thereof. 
     
     
       5. The apparatus of claim 1 which further comprises means for venting oxides of organic components of the contaminated soil which are produced during heating of the contaminated soil by the energy probe. 
     
     
       6. The apparatus of claim 1 wherein the oxygen rich material is a gas with a nitrogen content less than about 20% by weight. 
     
     
       7. The apparatus of claim 1 wherein the oxygen rich material is a gas with an oxygen content greater than about 80% by weight. 
     
     
       8. The apparatus of claim 1 wherein the energy probe is initially activated at a level which at least about 17 feet below grade level. 
     
     
       9. A method for in situ treatment and oxidation of waste materials in contaminated soil comprising the steps of: introducing an energy probe into the contaminated soil to a predetermined depth;   activating the energy probe after the probe is inserted to the predetermined depth to melt at least about one cubic foot of the soil;   introducing oxygen rich substances to the molten soil; and   controlling the amount of introduced oxygen to (a) preclude a reducing reaction between any carbon bearing components and any metallic components of the waste materials and to (b) produce metallic oxides from the metallic components which oxides dissolve into the molten waste material.   
     
     
       10. The method of claim 9 which further comprises the steps of: raising the energy probe above the predetermined starting depth while maintaining the energy probe in an activated state;   controlling the rate of ascent of the probe so that the contaminated soil which becomes adjacent to the probe during its ascent is melted and its organic and metallic components are oxidized; and   wherein the rate of ascent is controlled to permit the energy probe to superheat the adjacent contaminated soil and thereby produce enhanced opportunity for formation of metallic oxide crystals within the contaminated soil during solidification thereof.   
     
     
       11. The method of claim 9 which comprises the further step of introducing waste form modifiers into the molten contaminated soil to produce a basaltic rock from the resolidified contaminated soil. 
     
     
       12. The method of claim 9 which comprises the further step of introducing neucleation sites into the molten contaminated soil to enhance crystal formation within the contaminated soil during re-solidification thereof. 
     
     
       13. The method of claim 9 which comprises the further step of venting oxides of organic components of the contaminated soil which are produced during heating of the contaminated soil by the energy probe. 
     
     
       14. The method of claim 9 wherein the oxygen rich material is a gas with a nitrogen content less than about 20% by weight. 
     
     
       15. The method of claim 9 wherein the oxygen rich material is a gas with a oxygen content greater than about 80% by weight. 
     
     
       16. The method of claim 9 wherein the energy probe is initially activated at a level which is below grade level. 
     
     
       17. The method of claim 9 wherein the energy probe is initially activated at a level which at least about 17 feet below grade level. 
     
     
       18. The method of claim 9 wherein oxides of titanium and zirconium are introduced in suitable quantities to produce IEB IV. 
     
     
       19. The method of claim 9 wherein compounds having a large neutron adsorption cross-section are introduced into the molten contaminated soil thereby reducing the probability of a sustained nuclear reaction from spontaneous decay and release of neutrons in contaminated soils containing nucleotides.